Tertiary ester



Patented Feb. 10, 1953 TERTIARY ESTER Walter Kimel, Highland Park, N.J., assignor to Hofimann-La Roche Inc., Nutley, N. J., a. corporation ofNew Jersey No Drawing. Application June 5, 1951, Serial No. 230,075

2 Claims.

This invention relates to a novel chemical compound, and to processes ofpreparing and converting said compound. More particularly, the inventionis concerned with the new substance t-vinylisopropyl acetoacetate, whichcan also be designated 1,1-dimethyl-propen-2-y1 3-oxobutanoate, andwhich can be represented by the formula CHsCOCHzCOOC (CH3) 2CH=CH2 Thissubstance can be prepared by condensing 2-methyl-buten-3-ol-2 withdiketene, and the product can be converted by heating (with loss ofcarbon dioxide) into 2-methyl-hepten-2-one-6. The latter can beconverted to citral, geraniol or pseudoionone by known processes, andthus the invention is of interest to the pharmaceutical, perfume andsoap industries.

The invention is further disclosed in the following example, which isillustrative but not limitative thereof.

Ewample In a flask equipped with a stirrer, a thermometer, a droppingfunnel, and a drying tube, 0.3 g. of sodium was reacted with 86 g. (1.0mol) of 2-methyl-buten-3-ol-2. The solution was cooled to C. and 101 g.(1.2 mols) of diketene was added slowly, with emcient stirring, duringone hour, while maintaining the temperature at 0 C. The mixture was thenallowed to stand for 24 hours at 0 C.

The resulting dark orange solution was diluted with 200 cc. of ether andextracted three times with 150 cc. portions of saturated sodiumbicarbonate solution, and then washed with water until neutral. Theorganic solution was dried over calcium sulphate, and concentrated invacuo. The residue was fractionated under reduced pres- 2 sure to yieldt-vinylisopropyl acetoacetate, B. P. (8 mm.) 84-86 C.; n =l.4364.

39.0 g. (0.229 mol) of t-vinylisopropyl acetoacetate was placed in aflask equipped with a reflux condenser, a thermometer, and a finecapillary tube for the introduction of nitrogen. A slow stream ofnitrogen was introduced, and the ester was heated at a very gentlereflux for about 1 hours at which time the evolution of carbon dioxidehad ceased. The residue in the flask was fractionated under reducedpressure to yield 2 methyl hepten 2 one 6, B. P. (35 mm.) 83-35 C.; n=1.4369. The latter product was further identified by conversion to itssemicarbazone, M. P. 134.5-135.5 0., and by conversion to its2,4-dinitrophenylhydrazone, M. P. 863 C.

Certain subject matter disclosed but not claimed in this application isdisclosed and claimed in my divisional application Serial No. 271,644,filed February 14, 1952.

I claim:

1. The compound t-vinylisopropyl acetoacetate.

2. A process of preparing t-vinylisopropyl acetoacetate which comprisescondensing diketene with 2-methy1-buten-3-ol-2.

WALTER KIMEL.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,225,542 Allen Dec. 17, 19402,228,452 Gleason Jan. 14, 1941 2,351,366 Pohl June 13, 1944 2,395,012Reeder Feb. 19, 1946

1. THE COMPOUND T-VINYLISOPROPYL ACETOACETATE.